Miscellaneous. Ba 
range thus supplying the watershed of the Nepean itself is from 
four to five miles. The coast-range is there precipitous and broken, 
and about the heads of the Cordeaux is depressed, so that behind 
Kembla it only attains an elevation of about 1,320 feet. 
The upper portion of the rocks forming this broken and lofty 
plateau is composed of ‘Hawkesbury rocks’ (such as occur about 
Sydney), and below these sandstones come in the Coal-measures of 
the Illawarra in regular sequence; the lowest members of the series 
being the fossiliferous beds, equivalents of the Lower Carboniferous 
rocks of Europe. 
Masses and dykes of basalt and other similar igneous rocks have 
broken through this series, and have formed insulated hills on the 
plateau—such as Wanyanbilli, and others between the heads of the 
Cordeaux and the Mittagong, to the westward. That range is com- 
posed of igneous rocks, such as trachyte, basalt, and porphyry, and 
of metamorphic rocks which have been altered by the action of the 
former. Besides these, the whole surface of that wild, broken 
country, which is in parts densely wooded, consists of the Hawkes- 
bury rocks, and patches of alluvia or drift. There are no slates 
nor any quartziferous rocks besides the pebbly conglomerates of the 
Hawkesbury beds, except the altered hardened sandstone and shale 
from the base of Mittagong, and of which the drift is composed. 
The sandstones and Coal-measures occur in the same way on the 
south side of the Mittagong, and are similarly interspersed with 
trap-hills, such as Kinnoul; or porphyry, as at Mount Broughton. 
Farther from the coast, numerous hills of igneous rock break 
through, or are covered at their bases by the formations previously 
mentioned, from the fossiliferous beds to the coal and the Hawkes- 
bury beds, with here and there indications of the Wianamatta beds, 
which, though filling in the centre of Cumberland, and forming 
Razor Back, only reach in patches the elevations of the Mittagong. 
Such, then, is the country in which the alleged gold-field occurs. 
The interior features, as described by me, do not appear on Sir T. L. 
Mitchell’s map. ButI give them from my own explorations, having 
made myself familiar with all that part of the country by frequent 
traverses, and barometrical measurements of the heights. 
I may add, that the nearest point at which I know true slate-rocks 
to occur is in the lower part. of Bundanoon Creek, which rises ten 
or eleven miles south of Berrima, and falls into the Shoalhaven. 
Over all this region, on both sides of the Mittagong ranges, there 
are drift-patches and occasional alluvial deposits in hollows and 
creeks. And it is, therefore, not extraordinary, that such being the 
ease, and bearing in mind the auriferous region farther south, here 
and there particles of gold should have been deposited, when the 
local drift and that from a loftier horizon were distributed. 
Prima facie, then, there is no argument against the possibility or 
probability of some gold occurring in any of the head-waters of the 
Nepean. 
But that there should be any other than drift-gold, whether local 
or otherwise, is very unlikely, for the reasons I have stated. 
